There are more than 12,000 regional checklists in Avibase, offered in 9 different taxonomies, including synonyms more than 175 languages. Each checklist can be viewed with photos shared by the birding community, and also printed as PDF checklists for field use.

Pelecanus occidentalis occidentalis: West Indies and Caribbean to islands off Venezuela

Pelecanus occidentalis murphyi: breeds on the Pacific coast of northwestern South America (Colombia and Ecuador); disperses south to northern Chile

Pelecanus occidentalis urinator: Galapagos Islands

Pelecanus occidentalis carolinensis: breeds coastally in eastern United States (Maryland south to Florida and Texas), eastern Mexico, Belize, and Honduras; and on Pacific coasts of Honduras, Costa Rica, and Panama. Disperses north on Atlantic coast and south to eastern Brazil; and on Pacific coast, north to southern Mexico and south to Peru

Pelecanus occidentalis californicus: breeds from southern California (Channel Islands) south locally to northwestern Mexico (south to Sinaloa). disperses north and south along the coast